The present invention relates to a collaborative work support system utilizing a plurality of workstations or personal computers connected through a network, and more particularly to a collaborative work support system which permits control of extent of open and operation of an object displayed on a window shared by participants.
Various techniques have been proposed for tele-pointing, tele-writing and comment. Sarin, Sunil and Greif describe in "Computer-based Real-Time Conferencing System", Computer, Vol.18, No.10, October 1985 on a tele-pointing system in which each participant may have his own tele-pointer (hereinafter referred to as PO). A public PO which allows the viewing and the accessing to all participants is discussed in Stefic et al., "Beyond the Chalkboard: Computer Supports Collaboration and Problem Solving in Meetings", Comm. ACM, Vol.30, No.1, January 1987. The drawing on a shared window is realized by Watanabe et al., "Distributed Multiparty Desktop Conferencing System: MERMAID", Proc. CSCW90. Stefic et al. and Watanabe et al. provide a shared window viewable by all participants as well as a personal window for each participant which is viewable by only an individual participant. It is also known to display graphics by the tele-writing (hereinafter referred to as DO) on the shared window.
The techniques proposed by the above references are insufficient in the following points in that the PO and the DO are shared by all participants.
First, no consideration is paid on the ownership of a PO for each participant and the operation thereof on the shared window. Accordingly, no consideration is paid on the inhibition of the viewing of the PO of one participant to other participants on the shared window.
Secondly, as to the DO, the participants cannot grasp who among the participants drew a particular graphic. Further, if a participant does not want to disclose a graphic to other participants, he cannot place it on the shared window and must draw it on the personal window.
The above problems will occur when a non-real-time collaborative authoring system is to be constructed by using the techniques proposed by the above references.